The present invention relates to a head support mechanism in a magnetic card reader comprising a head support plate, which supports a magnetic head, and a leaf spring that applies pressure to the head support plate toward a magnetic card.
When a magnetic card having a magnetic strip is transferred on a card transferring path in a magnetic card reader, magnetic information on the magnetic strip is read out from or written onto the card by a magnetic head placed on the card transferring path. FIGS. 7(a)-7(b) show a magnetic head support mechanism of conventional technology. FIG. 7(a) is an overhead view, and FIG. 7(b) is a side view of a cross section.
As shown in FIGS. 7(a) and 7(b), magnetic heads 70 and 71 are placed next to each other in the direction perpendicular to the card transferring direction. Magnetic head 70 is supported by head support plate 72 while magnetic head 71 is supported by head support plate 73. Head support plates 72 and 73 are formed of a rigid material and restrained by two positioning pins 80 and 81 formed on a head support mechanism body (not shown) Accordingly, magnetic heads 70 and 71 supported by head support plates 72 and 73 can rock and move back and forth.
Leaf spring 74 is formed above head support plates 72 and 73. Leaf spring 74 is fixed to part 90 (see FIG. 7(b)) of the head support mechanism body (not shown) with fixing portions 91 and 92 such as screws. The end of leaf spring 74 is split into two pieces (arm portions); one of the arm portions, 75, applies pressure on head support plate 72 toward the magnetic card (downward in FIG. 7(b)) while other arm portion, 76, applies pressure on head support plate 73 toward the magnetic card (downward in FIG. 7(b)).
As shown in FIGS. 7(b) and 8, one end of arm portions 75 and 76, which is facing head support plate 72 and 73, respectively, is warped to form a hemisphere. A section of arm portions 75 and 76 at which arm portions 75 and 76 contact head support plates 72 and 73 has hemispheric projecting portions 77 and 78, respectively. Accordingly, projecting portion 77 of arm portion 75 applies pressure on head support plate 72 toward the magnetic card while projecting portion 78 of arm portion 76 applies pressure on head support plate 73 toward the magnetic card. As a result, magnetic heads 70 and 71 come in contact with the magnetic card with a given pressure applied by a pad placed across from magnetic heads 70, 71.
Movement of head support plates 72 and 73 needs to follow the warped shape of the magnetic card. Therefore, head support plates 72 and 73 can rock in the direction perpendicular to the card transferring direction with the two positioning pins 80 and 81 as an axis. Positioning pins 80 and 81 also function to establish an axis of a rocking motion of magnetic head 70 and 71.
However, head support plates 72 and 73 and leaf spring 74 are separate parts. Therefore, if the relative position of head support plates 72 and 73 and leaf spring 74 is not precise during assembly of these parts, projecting portions 77 and 78 will be displaced from the line between positioning pins 80 and 81. As a result, application of pressure by projecting portions 77 and 78 to head support plates 72 and 73 is no longer along the axis. Additionally, it is extremely troublesome to precisely position head support plates 72 and 73 and leaf plate 74 to enable projecting portions 77 and 78 to apply pressure to head support plates 72 and 73 on the line between positioning pins 80 and 81 towards the magnetic card.
The present invention intends to solve the above issues of conventional technology and to provide a head support mechanism in a magnetic card reader such that even when the alignment of the head support plates with the leaf spring is not precise, the leaf spring can continuously apply pressure to the head support plate at the desired position and the magnetic heads are brought in contact with a magnetic card with high accuracy.
The present invention provides a head support mechanism in a magnetic card reader comprising a head support plate that supports a magnetic head such that said magnetic head is able to rock and move in a plane perpendicular to the direction in which a magnetic card is transferred and a leaf spring for applying pressure to said head support plates towards the magnetic card such that the magnetic head comes in contact with said magnetic card. Formed on the head support plate is a projecting portion, which extends in a direction perpendicular to the card transferring direction and is provided for contacting a pressure applying portion formed on the leaf spring.